Are we talking about how to calculate a dice roll or how to represent it in Mendix? See this javascript for a nice dice representation: http://javascriptkit.com/script/script2/dice.shtml
You can use the Javascript snippet to place it in your form: https://appstore.home.mendix.com/link/app/43096/Incentro-Business-Acceleration/JavaScript-Snippet
You then just need some conditional visibility to show the correct throw.
Regards,
Ronald